2 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_ISNANL],
9 AC_REQUIRE([gl_MATH_H_DEFAULTS])
11 gl_HAVE_ISNANL_NO_LIBM
12 if test $gl_cv_func_isnanl_no_libm = no; then
13 gl_HAVE_ISNANL_IN_LIBM
14 if test $gl_cv_func_isnanl_in_libm = yes; then
18 if test $gl_cv_func_isnanl_no_libm = yes \
19 || test $gl_cv_func_isnanl_in_libm = yes; then
21 LIBS="$LIBS $ISNANL_LIBM"
24 case "$gl_cv_func_isnanl_works" in
25 *yes) gl_func_isnanl=yes ;;
26 *) gl_func_isnanl=no; ISNANL_LIBM= ;;
31 if test $gl_func_isnanl != yes; then
35 AC_SUBST([ISNANL_LIBM])
38 AC_DEFUN([gl_FUNC_ISNANL_NO_LIBM],
40 gl_HAVE_ISNANL_NO_LIBM
41 gl_func_isnanl_no_libm=$gl_cv_func_isnanl_no_libm
42 if test $gl_func_isnanl_no_libm = yes; then
44 case "$gl_cv_func_isnanl_works" in
46 *) gl_func_isnanl_no_libm=no ;;
49 if test $gl_func_isnanl_no_libm = yes; then
50 AC_DEFINE([HAVE_ISNANL_IN_LIBC], [1],
51 [Define if the isnan(long double) function is available in libc.])
57 dnl Pull in replacement isnanl definition. It does not need -lm.
58 AC_DEFUN([gl_BUILD_ISNANL],
61 gl_LONG_DOUBLE_EXPONENT_LOCATION
64 dnl Test whether isnanl() can be used without libm.
65 AC_DEFUN([gl_HAVE_ISNANL_NO_LIBM],
67 AC_CACHE_CHECK([whether isnan(long double) can be used without linking with libm],
68 [gl_cv_func_isnanl_no_libm],
75 # define isnanl(x) __builtin_isnanl ((long double)(x))
78 # define isnanl(x) isnan ((long double)(x))
81 [[return isnanl (x);]])],
82 [gl_cv_func_isnanl_no_libm=yes],
83 [gl_cv_func_isnanl_no_libm=no])
87 dnl Test whether isnanl() can be used with libm.
88 AC_DEFUN([gl_HAVE_ISNANL_IN_LIBM],
90 AC_CACHE_CHECK([whether isnan(long double) can be used with libm],
91 [gl_cv_func_isnanl_in_libm],
100 # define isnanl(x) __builtin_isnanl ((long double)(x))
103 # define isnanl(x) isnan ((long double)(x))
106 [[return isnanl (x);]])],
107 [gl_cv_func_isnanl_in_libm=yes],
108 [gl_cv_func_isnanl_in_libm=no])
113 dnl Test whether isnanl() recognizes all numbers which are neither finite nor
114 dnl infinite. This test fails e.g. on NetBSD/i386 and on glibc/ia64.
115 dnl Also, the GCC >= 4.0 built-in __builtin_isnanl does not pass the tests
116 dnl - for pseudo-denormals on i686 and x86_64,
117 dnl - for pseudo-zeroes, unnormalized numbers, and pseudo-denormals on ia64.
118 AC_DEFUN([gl_FUNC_ISNANL_WORKS],
120 AC_REQUIRE([AC_PROG_CC])
121 AC_REQUIRE([gl_BIGENDIAN])
122 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
123 AC_CACHE_CHECK([whether isnanl works], [gl_cv_func_isnanl_works],
132 # define isnanl(x) __builtin_isnanl ((long double)(x))
135 # define isnanl(x) isnan ((long double)(x))
138 ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int))
139 typedef union { unsigned int word[NWORDS]; long double value; }
141 /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the
142 runtime type conversion. */
144 static long double NaNl ()
150 # define NaNl() (0.0L / 0.0L)
156 if (!isnanl (NaNl ()))
160 memory_long_double m;
163 /* The isnanl function should be immune against changes in the sign bit and
164 in the mantissa bits. The xor operation twiddles a bit that can only be
165 a sign bit or a mantissa bit (since the exponent never extends to
168 m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1);
169 for (i = 0; i < NWORDS; i++)
171 if (!isnanl (m.value))
175 #if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_))
176 /* Representation of an 80-bit 'long double' as an initializer for a sequence
177 of 'unsigned int' words. */
178 # ifdef WORDS_BIGENDIAN
179 # define LDBL80_WORDS(exponent,manthi,mantlo) \
180 { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \
181 ((unsigned int) (manthi) << 16) | (unsigned int) (mantlo) >> 16), \
182 (unsigned int) (mantlo) << 16 \
185 # define LDBL80_WORDS(exponent,manthi,mantlo) \
186 { mantlo, manthi, exponent }
189 static memory_long_double x =
190 { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) };
191 if (!isnanl (x.value))
195 /* Signalling NaN. */
196 static memory_long_double x =
197 { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) };
198 if (!isnanl (x.value))
201 /* The isnanl function should recognize Pseudo-NaNs, Pseudo-Infinities,
202 Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
203 Intel IA-64 Architecture Software Developer's Manual, Volume 1:
204 Application Architecture.
205 Table 5-2 "Floating-Point Register Encodings"
206 Figure 5-6 "Memory to Floating-Point Register Data Translation"
209 static memory_long_double x =
210 { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
211 if (!isnanl (x.value))
214 { /* Pseudo-Infinity. */
215 static memory_long_double x =
216 { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
217 if (!isnanl (x.value))
221 static memory_long_double x =
222 { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
223 if (!isnanl (x.value))
226 { /* Unnormalized number. */
227 static memory_long_double x =
228 { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
229 if (!isnanl (x.value))
232 { /* Pseudo-Denormal. */
233 static memory_long_double x =
234 { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
235 if (!isnanl (x.value))
242 [gl_cv_func_isnanl_works=yes],
243 [gl_cv_func_isnanl_works=no],
245 # Guess no on ia64, x86_64, i386.
246 ia64 | x86_64 | i*86) gl_cv_func_isnanl_works="guessing no";;
249 netbsd*) gl_cv_func_isnanl_works="guessing no";;
250 *) gl_cv_func_isnanl_works="guessing yes";;